Berlin 2015 – scientific programme

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BP: Fachverband Biologische Physik

BP 14: Posters: Neurophysics

BP 14.9: Poster

Monday, March 16, 2015, 17:30–19:30, Poster A

Switching dynamics in subnetworks of spiking neural networks — •Fereshteh Lagzi and Stefan Rotter — Bernstein Center Freiburg and Faculty of Biology, Freiburg, Germany

The network under study is comprised of three subnetworks of either excitatory or inhibitory leaky integrate-and-fire neurons. The excitatory and inhibitory weights are arranged to establish and maintain a balance between excitation and inhibition for a constant external drive. Each subnetwork has a random connectivity with fixed in-degree and fixed out-degree for all neurons belonging to a particular population. Neurons in different subnetworks are also randomly connected with the same probability; however, depending on their identity, the connection weight is scaled by a factor. We observed that for a certain regime of ratios of the “within” versus “between” connection weights (bifurcation parameter), the network activation spontaneously switches between the two subnetworks of the same identity (winnerless competition). In our model, this phenomenon is explained by a set of coupled stochastic differential equations of Lotka-Volterra type that exhibit a competition between the subnetworks. The deterministic phase portrait is characterized by two attractors and a saddle node, its stochastic component is essentially given by the multiplicative inherent noise of the system.

Supported by the German Ministry of Education and Research (BFNT Freiburg*Tübingen, grant 01GQ0830) and the German Research Foundation (DFG, grant EXC 1086).